This invention relates to a method of and means for producing combustible products from heavy residue oil and more particularly to a method or and means for producing combustible products from asphaltene.
Recently the requirement for better quality and lighter fuels for among other things to comply with the air pollution regulations has been increasing. Conventionally, distillation of fuel leaves a heavy residue having bitumen characteristics which is cracked using a catalyzer such that cracking takes place at a temperature of a few hundred degrees C. or higher. After this cracking, an even less friendly residue remains called asphaltene which is difficult and uneconomical to crack since it poisons the catalysts and also requires high temperatures which usually results in large investments. Thus, conventionally, asphaltene is blended with another fuel of relatively high caloric or heating value and then sold since asphaltene itself does not possess good qualities for combustion. Evenso, under present conditions more and more asphaltene is being produced.
In U.S. Pat. No. 5,372,708, a process for the thermal dissolution of oil shale which is rich in mineral constituents is disclosed. In the process disclosed in the ""708 patent, a mixture of these so-called low grade oil shales with a fraction of heavy fuel having a boiling point above 350xc2x0 C. is cracked and a hydrocarbon fuel having a boiling point up to 350xc2x0 C. is recovered from the gases and vapors leaving the cracking reactor with the residue produced having mineral constituents being recovered and used as a raw material for various purposes, such as chemical products, like asphaltene, etc. or for combusting in the cracker for producing hot gases which heat the mixture being cracked.
It is therefore an object of the present invention to provide a new and improved method of and means for producing combustible gases from heavy fuel residue such as asphaltene which substantially overcomes or significantly reduces the disadvantages outlined above.
In accordance with present invention, a method for producing combustible products such as a low viscosity liquid fuel and fuel gas is provided comprising pyrolyzing asphaltene together with a low grade solid fuel containing materials or minerals which have catalytic properties such as oil shale, certain types of low grade coal, etc. Preferably according to the present invention the step of pyrolyzing asphaltene together with oil shale is carried out by adding asphaltene to a pyrolyzer, adding oil shale to a pyrolyzer, combusting carbonaceous material remaining in the pyrolyzer by supplying the remaining carbonaceous material to a combustor preferably separate from the pyrolyzer and adding ash produced by the combustion of the carbonaceous material to the pyrolyzer for supplying the heat for the pyrolysis process. Such pyrolysis is advantageous since oil shale and other such materials have many catalytic qualities which can aid in the cracking of the asphaltene as well as in capturing sulfur or compounds of sulfur. Furthermore, the use of ash for providing the heat for the pyrolysis process is also advantageous since more catalysts are added to the material being pyrolyzed.
In addition, in a further embodiment of the present invention, a method of producing combustible products such as low viscosity fuel and fuel gas is also provided comprising pyrolyzing asphaltene together with ash produced from low grade fuel such as oil shale. In this embodiment less fuel is obtained.
Moreover, the present invention comprises providing apparatus for carrying the above mentioned method steps of the present invention.